Practically since the first was invented, septic tanks have permitted improperly processed wastewater to escape when the tank was not regularly cleaned. If not removed on time, sludge inevitably accumulated to the point where the settling process became significantly impaired.
Various attempts have been made in the past to cause sludge to settle at the bottom of the septic tank. U.S. Pat. No. 3,261,779 to Sullins et al discloses a multi-compartmented septic tank provided with conduits that conveyed material from the top of one chamber to the bottom of the next via a conduit extending through a partition wall and downwardly into the next chamber. U.S. Pat. No. 4,325,823 to Grahm discloses a multi-chambered septic tank provided with a baffle extending downwardly from the top thereof in proximity to one of the partition walls. U.S. Pat. No. 4,505,813 to Graves discloses a relatively short partition or baffle extending downwardly from the top of one of the chambers adjacent to an opening in one of the partition walls. The passageways disclosed in these references were, among other reasons, provided to prevent sludge from reaching the final clarification chamber. However, sludge would tend to build up in the first few chambers, rendering them ineffective at trapping sludge and increasing the concentration of sludge in ensuing chambers. It was quite possible for sludge to reach the leach bed into which the output of the septic tank was fed, thereby creating potential harm to the environment.
Thus, the present inventor was faced with the problems of providing a multi-compartmented septic tank with means for preventing a damaging build-up of sludge and for ensuring that the output of the septic tank is properly decontaminated whenever operating.